dep: fix equality check of packages
dep: fix equality check of packages

Looks like there is an Eq method on LockedProject

This makes `dep ensure -update` on dep itself "work" (it produced
something that won't build though because we're on gps master and that
doesn't work with our Mastermind semver constraints).

golang/dep,EwanValentine/dep,golang/dep,ibrasho-forks/dep,EwanValentine/dep,golang/dep,ibrasho-forks/dep